Table 3.
Unadjusted and adjusted odds ratios for risk factors in singleton moderate to late preterm 32 + 0 to 36 + 6 weeks of gestational age fetuses in breech and in cephalic presentations during 2004–2014 in Finland
| 32–36 Weeks of gestation | Breech (N = 1854) | Cephalic (N = 24 997) | P value | Odds ratio (95% Cl) | Adjusted odds ratio (95% CI) |
|---|---|---|---|---|---|
| Maternal age < 25 | 39 (2.1%) | 741 (3.0%) | 0.020 | 0.70 (0.51–0.97) | 0.68 (0.48–0.94) |
| Maternal age ≥ 35 | 451 (24.3%) | 5409 (21.6%) | < 0.001 | 1.16 (1.04–1.30) | 1.24 (1.10–1.39) |
| Smoking | 293 (15.8%) | 4426 (17.7%) | 0.139 | 0.87 (0.77–0.99) | 0.91 (0.79–1.03) |
| Maternal BMI ≥ 25 | 202 (10.9%) | 3359 (13.4%) | 0.004 | 0.79 (0.68–0.92) | 0.75 (0.62–0.91) |
| Maternal BMI ≥ 30 | 80 (4.3%) | 1175 (4.7%) | 0.120 | 0.91 (0.73–1.15) | 1.26 (0.94–1.69) |
| Nulliparity | 1048 (56.5%) | 12,235 (48.9%) | < 0.001 | 1.36 (1.23–1.49) | 1.43 (1.27–1.60) |
| Parity ≥ 3 | 158 (8.5%) | 2665 (10.7%) | 0.134 | 0.78 (0.66–0.92) | 0.87 (0.73–1.04) |
| Maternal hypothyroidism | 21 (1.1%) | 259 (1.0%) | 0.360 | 1.09 (0.70–1.71) | 1.24 (0.78–1.96) |
| Maternal hyperthyroidism | 6 (0.3%) | 48 (0.2%) | 0.100 | 1.69 (0.72–3.95) | 2.06 (0.87–4.87) |
| Pre-gestational diabetes treated with insulin | 5 (0.3%) | 118 (0.5%) | 0.066 | 0.57 (0.23–1.40) | 0.76 (0.57–1.02) |
| Gestational diabetes | 159 (8.6%) | 2481 (9.9%) | 0.099 | 0.85 (0.72–1.01) | 0.86 (0.72–1.03) |
| Pre-eclampsia/hypertension | 161 (8.7%) | 2232 (8.9%) | 0.394 | 0.97 (0.82–1.15) | 0.93 (0.78–1.10) |
| Previous cesarean section | 255 (13.8%) | 3423 (13.7%) | < 0.001 | 1.01 (0.88–1.15) | 1.31 (1.12–1.53) |
| IVF | 75 (4.0%) | 900 (3.6%) | 0.854 | 1.13 (0.89–1.44) | 0.98 (0.76–1.25) |
| Maternal care for (suspected) damage to fetus by alcohol/drugs | 3 (0.2%) | 39 (0.2%) | 0.760 | 1.04 (0.32–3.36) | 0.83 (0.25–2.76) |
| Placenta praevia | 36 (1.9%) | 624 (2.5%) | 0.240 | 0.77 (0.55–1.09) | 0.81 (0.58–1.15) |
| Placental abruption | 27 (1.5%) | 414 (1.7%) | 0.763 | 0.88 (0.59–1.30) | 0.94 (0.63–1.40) |
| PPROM | 437 (23.6%) | 3968 (15.9%) | < 0.001 | 1.63 (1.46–1.83) | 1.58 (1.41–1.78) |
| Oligohydramnios | 55 (3.0%) | 191 (0.8%) | < 0.001 | 3.97 (2.93–5.38) | 3.60 (2.63–4.92) |
| Congenital anomaly | 362 (19.5%) | 3690 (14.8%) | < 0.001 | 1.40 (1.24–1.58) | 1.37 (1.22–1.55) |
| Female sex | 890 (48.0%) | 10,817 (43.3%) | < 0.001 | 1.21 (1.10–1.33) | 1.22 (1.11–1.34) |
| Birthweight < 10th percentile | 205 (11.1%) | 2012 (8.0%) | 0.003 | 1.42 (1.22–1.65) | 1.31 (1.10–1.56) |
| Birthweight > 97th percentile | 41 (2.2%) | 1162 (4.6%) | 0.004 | 0.46 (0.34–0.64) | 0.60 (0.42–0.85) |
BMI body mass index, IVF in vitro fertilization, PPROM preterm premature rupture of membranes